There have been many long-lasting stateless societies, but I wouldn’t call them utopias, because utopias cant’t exist. Nomadic native societies around the world in many instances were stateless and anarchistic in nature. Opt out possible, no taxes, no jails, no hard chain of command. Before them hunter gatherer societies had anarchistic structures too. In these instances societies operated and functioned for millennia and people within in many instances had good, long and fulfilling lives. And they were truly free.